Chemistry Class 12 NCERT Solutions: Chapter 13 Amines Part 12

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Q: 11. Complete the following reactions:

(i)

(ii)

(iii)

(iv)

(v)

(vi)

(vii)

Answer:

(ii)

(iii)>

(iv)

(v)

Q 11 v Structure of Aniline and 2, 4, 6-Tribromoaniline

Q 11 v Structure of Aniline and 2, 4, 6-Tribromoaniline

Q 11 v Structure of Aniline and 2, 4, 6-Tribromoaniline

(vi)

(vii)

Q: 12. Why cannot aromatic primary amines be prepared by Gabriel phthalimide synthesis?

Answer:

Gabriel phthalimide synthesis is used for the preparation of aliphatic primary amines. It involves nucleophilic substitution of alkyl halides by the anion formed by the phthalimide.

Q 12 1 Structure of Gabriel Phthalimide Synthesis

Q 12 1 Structure of Gabriel Phthalimide Synthesis

Q 12 1 Structure of Gabriel Phthalimide Synthesis

But aryl halides do not undergo nucleophilic substitution with the anion formed by the phthalimide.

Q 12 2 Structure of Gabriel Phthalimide Synthesis

Q 12 2 Structure of Gabriel Phthalimide Synthesis

Q 12 2 Structure of Gabriel Phthalimide Synthesis

Hence, aromatic primary amines cannot be prepared by this process.

Q: 13. Write the reactions of (i) aromatic and (ii) aliphatic primary amines with nitrous acid.

Answer:

(i) Aromatic amines react with nitrous acid (prepared in situ from and a mineral acid such as ) at to form stable aromatic diazonium salts i.e., and .

Q 13 i Aromatic Amines React with Nitrous Acid

Q 13 I Aromatic Amines React With Nitrous Acid

Q 13 i Aromatic Amines React with Nitrous Acid

(ii) Aliphatic primary amines react with nitrous acid (prepared in situ from and a mineral acid such as ) to form unstable aliphatic diazonium salts, which further produce alcohol and with the evolution of gas.

Q 13 ii Aliphatic Primary Amines React with Nitrous Acid

Q 13 Ii Aliphatic Primary Amines React With Nitrous Acid

Q 13 ii Aliphatic Primary Amines React with Nitrous Acid